I will admit that I am not a pilot, so forgive me if the following question is a simple one.

I know that there many different kinds of approaches (such as ILS approach, RNAV approach, NDB approach, VOR/DME approach, and visual approach). I'm still trying to learn the differences between these types of approaches. But what I'd like to focus on is the "RNAV Approach".

I understand that RNAV stands for "aRea NAVigation". When a terminal controller that manages aircraft arrivals to the airport, he/she will say to the pilot "you are cleared for the RNAV (insert runway #) approach".

Recently in Ottawa (CYOW), I have heard ATC tell pilots that they are cleared for the "RNAV Z" or "RNAV Y" approach (RNAV Zulu and RNAV Yankee, respectively).

The question is: what is the difference between an RNAV Z/RNAV Y approach versus an actual RNAV approach?

what is the difference between an RNAV Z/RNAV Y approach versus an actual RNAV approach?

In the case of Ottawa (and the rest of Canada from what I've seen) where there are two RNAV approaches to the same runway, the RNAV "Y" approach refers to the "RNP" (Required Navigation Performance) approach, while the RNAV "Z" refers to the RNAV "GNSS" (Global Navigation Satellite System) approach.

They are both RNAV approaches that use GPS/GNSS but basically the RNP (RNAV Y) is more precise. For example runway 25 in Ottawa, the minimums for the RNAV Y are 250 feet (agl) and 1 mile vs the RNAV Z minimums of 390 feet (agl) and 1.25 miles.

The lateral design of the approaches is also different, the RNP approach can utilize a shorter transition off the STAR (called a "shortgate"), and each have different Final Approach Fixes.

what is the difference between an RNAV Z/RNAV Y approach versus an actual RNAV approach?

In the case of Ottawa (and the rest of Canada from what I've seen) where there are two RNAV approaches to the same runway, the RNAV "Y" approach refers to the "RNP" (Required Navigation Performance) approach, while the RNAV "Z" refers to the RNAV "GNSS" (Global Navigation Satellite System) approach.

They are both RNAV approaches that use GPS/GNSS but basically the RNP (RNAV Y) is more precise. For example runway 25 in Ottawa, the minimums for the RNAV Y are 250 feet (agl) and 1 mile vs the RNAV Z minimums of 390 feet (agl) and 1.25 miles.

The lateral design of the approaches is also different, the RNP approach can utilize a shorter transition off the STAR (called a "shortgate"), and each have different Final Approach Fixes.

For completeness: you can also have a lettered VOR or NDB approach, like VOR-A without a runway specified, and this means that the approach does not leave you aligned with a landing runway; you then "circle to land" on whatever the active is.

A visual approach is almost never charted, although some famous ones such as the River Visual into DCA are. If you are just "cleared for the visual" you make the approach in visual conditions same as if you are VFR. You won't be cleared for it until you report the airport in sight.